Hash::Case - base class for hashes with key-casing requirements

       Hash::Case is the base class for various classes which tie special treatment for the casing of keys.  Be
       aware of the differences in implementation: "Lower" and "Upper" are tied native hashes: these hashes have
       no need for hidden fields or other assisting data structured.  A case "Preserve" hash will actually
       create three hashes.

       The following strategies are implemented:

       •   Hash::Case::Lower (native hash)

           Keys  are  always  considered  lower case. The internals of this module translate any incoming key to
           lower case before it is used.

       •   Hash::Case::Upper (native hash)

           Like the ::Lower, but then all keys are always translated into upper case.  This module can be of use
           for some databases, which do translate everything to capitals as well.  To avoid confusion,  you  may
           want to have you own internal Perl hash do this as well.

       •   Hash::Case::Preserve

           The actual casing is ignored, but not forgotten.

        Hash::Case
          is a Tie::StdHash

        Hash::Case is extended by
          Hash::Case::Lower
          Hash::Case::Preserve
          Hash::Case::Upper

       Copyrights 2002-2020 by [Mark Overmeer <markov@cpan.org>]. For other contributors see ChangeLog.

       This  program  is  free  software;  you can redistribute it and/or modify it under the same terms as Perl
       itself.  See http://dev.perl.org/licenses/

perl v5.36.0                                       2022-10-13                                    Hash::Case(3pm)

Constructors
       $obj->addHashData(HASH)
           Add  the  data  of a hash (passed as reference) to the created tied hash.  The existing values in the
           hash remain, the keys are adapted to the needs of the the casing.

       $obj->addPairs(PAIRS)
           Specify an even length list of alternating key and value to be stored in the hash.

       $obj->setHash(HASH)
           The functionality differs for native and wrapper hashes.  For native hashes,  this  is  the  same  as
           first  clearing  the  hash,  and  then a call to addHashData().  Wrapper hashes will use the hash you
           specify here to store the data, and re-create the mapping hash.

       tie(HASH, TIE, [VALUES,] OPTIONS)
           Tie the HASH with the TIE package which extends Hash::Case.  The OPTIONS differ  per  implementation:
           read  the  manual  page  for  the  package  you  actually use.  The VALUES is a reference to an array
           containing key-value pairs, or a reference to a hash: they fill the initial hash.

           example:

            my %x;
            tie %x, 'Hash::Case::Lower';
            $x{Upper} = 3;
            print keys %x;       # 'upper'

            my @y = (ABC => 3, DeF => 4);
            tie %x, 'Hash::Case::Lower', \@y;
            print keys %x;       # 'abc' 'def'

            my %z = (ABC => 3, DeF => 4);
            tie %x, 'Hash::Case::Lower', \%z;

       Hash::Case - base class for hashes with key-casing requirements

       This module is part of Hash-Case  distribution  version  1.05,  built  on  February  06,  2020.  Website:
       http://perl.overmeer.net/CPAN/

        use Hash::Case::Lower;
        tie my(%lchash), 'Hash::Case::Lower';
        $lchash{StraNGeKeY} = 3;
        print keys %lchash;  # strangekey